The issue can be fixed by updating file doctrine-dbal.php from:$classLoader = new \Doctrine\Common\ClassLoader('Symfony', 'Doctrine');
to:$classLoader = new \Doctrine\Common\ClassLoader('Symfony');
so the Symfony Console package can be used like the PEAR package.xml requires.

NOTE: I did not want to submit a GitHub pull request for this because it seems like it would break your Git and Composer installs

In some cases the Comparator class returns multiple drops for the same foreign key.
Specifically, in case you have two tables, A & B, with A having a foreign key FK
referencing B, if you drop table B, the resulting diff shows this FK twice,
once on the diff->orphanedForeignKeys array as we're deleting B, and another on
the diff->changedTables array as table A is also being modified. As a result of this you
get the DROP FOREIGN KEY instruction twice in the final SQL.